#include <iostream>
using namespace std;

// 调用内联函数，在编译时直接替换语句，节约运行时间
inline double circle(double r) {
    double PI = 3.14;
    return PI * r * r;
} 

int main() {
    for (int i = 1; i <= 3; i++)
    cout << "r = " << i << "area = " << circle(i) << endl;

    return 0;
}